Structure and Oligomers Distribution of Commercial Tara (Caesalpina spinosa) Hydrolysable Tannin

Abstract

Solvent extracted commercial Tara tanninextract have been examined by Matrix Assisted LaserDesorption/Ionisation Time-of-Flight (MALDI-TOF)mass spectrometry and by High Pressure LiquidChromatography (HPLC). The Tara extract has beenfound to be composed of a series of oligomers ofpolygallic acid attached by an ester link to one quinicacid. They constitute the oligomers in higherproportion in the extract. Other polygallic chains linkedto one only or two repeating units such as caffeic acidand methylated quinic, methylated gallic andmethylated caffeic acids are also present. Negativeion mode MALDI-TOF showed that somecarbohydrate residues appear to still be present,linked to the polyphenolic material of the extract buttheir proportion is very low as would be expected of asolvent extracted tannin.

Keywords

• Tara extract
• tannin
• hydrolysable tannins
• structure
• wood
• MALDI
• HPLC
• polygallic oligomers
• quinic acid
• Caesalpina spinosa